Truck refrigeration system



April 7, 1959 Filed Sept. 12, 1955 TRUCK REFRIGERATION SYSTEM 4Sheets-Sheet 1 INVENTORS ORTQN S. McGUFFEY JAMES W. MCGUFFEY WZLM WATTORNEYS o. s. MGGUFFEY ET AL 7 2,880,595

TRUCK REFRIGERATION SYSTEM April 7, 1-959 4 Sheets-Sheet 2 Filed Sept.12, 1955 INVENTORS' ORTON S.McGUFFEY JAMES w. McGUFFEY ATTORNEYS April7, 1959 s, MCGUF'FEY ET AL I 2,880,595

TRUCK REFRIGERATION SYSTEM 4 Sheets-Sheet 3 Filed Sept. 12, 1955INVENTORS ORTON S. McGUFFEY JAMES W.MCGUFFEY Wm Muzzy ATTORNEYS April 7,1959 o. s. MGGUFFEY ETAL 2,880,595

TRUCK REFRIGERATION SYSTEM Filed Sept. 12, 1955 "4 Sheets-Sheet 4INVENTORS ORTON s. McGUFFEY BY JAMES W.McGUFFEY United States Patent2,880,595 TRUCK REFRIGERATION SYSTEM Application September 12, 1955,Serial No. 533,618 7 Claims. (Cl. 62242) Lansing,

Lan-

The present invention relates to improvements in a mobile refrigerationsystem such as is commonly built into refrigerated delivery trucks,cross-country refrigerated trucks and truck-trailer combinations, etc.It is a general object of the invention to provide a refrigeratingsystem for installations of this character which is greatly improved inpoint of its relative simplicity and inexpensiveness, its lightness inweight and compactness, its en. tire reliability in operation, whetherpowered by a direct driving connection from the vehicle engine intransit or from a stand-by electrical motor, and by its inherentincapability of becoming damaged or imperfectly inoperative underconditions likely to be encountered in normal use.

More specifically, it is an object of the invention to provide a mobilerefrigeration system of the foregoing character made up of an assemblageof more or less standard refrigerating system components, such as acompressor, condenser, heat exchange unit, etc., in which thesecomponents are arranged in an improved fashion in respect to the vehicleon which the installation is made. In accordance with the invention, aswell as in conformity with customary practice, the heat exchange unitincludes a coil, fan, and motor, as well as expansion and frost controlvalves which are mounted within the interior of a body compartment tothe rear of the vehicle which is to be refrigerated. For the rest, theinvention contemplates the mounting of a compressor unit which ismechanically actuated by the vehicle engine or a standby motor, alongwith the motor itself and an engine or motor driven pump or like powersupply device or unit as a single combined sub-assembly or package onthe chassis of the vehicle. This is accomplished by the use of a commoncompressor pump motor support beneath the vehicle chassis, whereas thecondenser unit is mounted along iwth its associated fan and fan motor(either hydraulically or electrically driven in accordance with thecharacter of the power supply device or unit) at an elevated point,preferably forwardly of and adjacent the top of the compartment to berefrigerated. A condenser unit so installed has the benefiit of thecooling air stream set up in the movement of the vehicle, as well asbeing positioned to receive the least dirt and possibility of damage byimpact.

Another object of the invention is to provide a refrigerationinstallation of the sort described characterized by provisions to driveits compressor and power supply device either directly from the vehicleengine or by a stand-by motor mounted in common with the compressor andpower device unit, in which there is an improved.

direct driving connection from the vehicle engine to an auxiliary driveshaft, mounted on the common support for those instrumentalities. Suchdirect drive avoids the need for a power take-off unit.

To this end, and in order to avoid cluttering the space beneath theengine hood or bonnet with refrigerator driving structure, making accessdiflicult to the engine parts, an electrically controlled clutch ismounted on a cush- Patented Apr. 7, 1959 ice ioned support beneath theforward end of the engine crankshaft, the clutch being driven by abelt-pulley ar-, rangement from the latter. The direct drive from theelectric clutch rearwardly to the compressor unit referred to above iseffected through the agency of a flexible shaft supported by the vehiclechassis and extending beneath the engine and operators cab, which shaftis coupled directly to the auxiliary drive shaft of the compressor unit.An installation results which is extremely compact and convenientlylocated, yet which is relatively inexpensive and is reliable inoperation.

It is a further object of the invention to provide an engine drivenrefrigeration system of the type described in which provisions are madeto insure against undue' shock to the transmission when therefrigeration system is cut into operation, as under control of asuitable automatic thermostatic control device, when the vehicle isengine driven in transit. It is evident that if this were accompanied bya positively engaging type of mechanical clutch, with the vehicletraveling at a considerable road speed, a destructive shock would beinevitable which, if applied to a flexible shaft type of driveconnection as contemplated by the invention, would unduly strain thesame. Accordingly, the application of the electric clutch energizingpower is effected in a stepped or gradual manner, pursuant to theinvention, in such manner that when the need for additionalrefrigeration is signaled by the automatic thermostatic control, theusual clutch magnet will be energized under partial current for apredetermined period, amounting to, say, three seconds to five seconds,after which full clutch applying voltage comes into play to lock theclutch and complete a direct, non-slip drive rearwardly to the auxiliarycompressor drive shaft mounted by the chassis of the vehicle. With anarrange-' ment of this sort, the transition into the engine-drivenrefrigerating phase is practically unnoticeable to an occupant of thetruck vehicle cab when traveling at relatively high road speed.

As a further feature, it is an object of the invention to provide asystem in which the electric stand-by motor, by which the compressor andhydraulic or electric generating unit of the system are actuated in alayover phase, is protected against damage during in-transit drive ofthe system from the vehicle engine. This takes the form of a connectionof the motor to the auxiliary drive shaft of the compressor through anoverrunning or oneway clutch; the result being that while the enginewill drive the auxiliary shaft and compressor when running, assuming theelectric clutch and flexible shaft drive for the auxiliary clutch iseffective, and the motor will also drive the auxiliary shaft whenenergized, the driven auxiliary shaft can under no circumstances drivethe motor.

The importance of such provision will be appreciated when it isunderstood that, whereas the compressor will be correctly driven at aspeed of approximately 450 r.p.m.

by a one horsepower electric motor operating at 1,750 in stand-byoperation, the compressor can be op-' suming that a condenser fan and aheat exchangeblower fan are driven by a hydraulic or electric powergenerating unit, which in turn has a common drive from the vehicleengine or from a stand-by motor in the fashion described, it is seenthat these fans will be driven at'a speed exactly proportional to thecompressor speed. 'If

{9 the compressor runs at high speed and produces considerablerefrigerating effect, the condenser and blower fans will also run athigh speed enabling the former to handle the refrigeration effectproduced by the compressor and the latter to dissipate the refrigerationeffect in the compartment to be refrigerated.

Yet another object of the invention is to provide a mobile truckrefrigeration system as outlined above, which may be installed on trucksof various types with little or no modification or alteration of thetruck. Thus, the invention affords, in its preferred embodiment, acommon mount for a compressor, a stand-by motor, a power supply device,which may be hydraulic or electric, and auxiliary shafting by which thecompressor and power supply units are selectively engine or motordriven, under control of automatic instrumentalities which may also bemounted on this common support. Simple bracket means are associated withthe support to rigidly but releasably clamp the sub-assembly justdescribed to the vehicle chassis; and the whole operation ofinstallation of the entire system is performed in a greatly reduced timeand by fewer personnel than has been possible with comparable mobilerefrigerating systems available to the trade.

Various ramifications in the positional arrangement of componentscontemplated by the invention are possible. An arrangement which has thecondenser forwardly and upwardly of the refrigerated compartment, thecompressor, stand-by motor, power supply sub-assembly positioned on aspecial common mount beneath and to one side of the chassis at thedepending side skirt of the compartment (being with slight modificationreversed to the opposite side of the chassis), the evaporator coil-heatexchange unit at an elevated location within the forward end of therefrigerated compartment, and an engine drive connection direct from theforward end of the vehicle and beneath the engine and chassis to thecompressor-motorpower supply sub-assembly, involving a clutch mountedbeneath the engine crankshaft and out of interference with engine parts.This is an arrangement which presents manifold advantages in regard tosimplicity of construction, simplicity, ease and speed in installation,compactness and lightness in weight, and accessibility for inspectionand servicing. Power is simply and directly derived in transit withoutthe complication of a power take-01f, which is objectionable from manystandpoints and is useable with an automatic type transmission only atgreat expense. The electric stand-by motor is de-clutched during roadoperation, under which the only limiting consideration as to the maximumspeed of operation of the compressor is the maximum speed at which itcan receive its drive from the engine.

The foregoing as well as other objects will be made more apparent asthis description proceeds, especially when considered in connection withthe accompanying drawings wherein:

Fig. 1 is an elevational view, partially broken away, generallyillustrating positional and operational relationships of variouscomponents of the improved refrigeration system to a conventional enginedriven truck, in accordance with the invention;

Fig. 2 is a fragmentary view, illustrating the forward end of anelectric clutchcontrolled, flexible shaft engine drive connection forthe compressor of the system, as well as provision by which this forwardend is connected beneath a cross frame of the vehicle to be driven bythe engine crankshaft of the latter;

Fig. 3 is a fragmentary elevational view, partially in verticallylongitudinal section, illustrating the rear extremity of the flexibleshaft connection of Fig. 2 and the provisions for mounting the same anddrivingly connecting it with an auxiliary drive shaft of the system, aswell as showing bclt-pulley provisions for connecting partially in axialsection,

this auxiliary shaft to the compressor and stand-by motor of the system.

Fig. 4 is a view in section along line 44 of Fig. 3 depicting thearrangement of compressor, motor, and power generating unit which aredriven by the pulley provisions of Fig. 3, as well as a common supportby means of which these units are carried by the chassis of a vehicle;

Fig. 5 is a view in side elevation of a bracket support by which thesub-assembly of Figs. 3 and 4 is conveniently and interchangeablymounted upon the vehicle chassis;

Fig. 5A is a fragmentary view in end elevation of the supporting bracketof Fig. 5, indicating the manner in which it sustains a supportingplatform for the subassembly referred to;

Fig. 6 is a schematic diagram showing in a general way the wiring andautomatic control provisions for the stand-by motor and electricallyenergizable clutch of the system; and

Fig. 7 is a schematic general layout of the system of the invention.

Referring first to Figs. 1 and 7 of the drawings, showing the overallararngement and relationship of parts to a conventional commercialautomotive truck 10, characterized by a cab 11 forwardly of a van-likebody 12, the interior 13 of which is to be refrigerated, the referencenumeral 14 generally designates a compressor, motor, and power supplyunit of the improved system, which is mounted to one side of the chassis15 of the vehicle; the reference numeral 16 generally designates theheat exchange, evaporator and blower unit of the system, which ismounted within the interior 13 adjacent the upper, forward end thereof,and is of conventional construction, including a hydraulically orelectrically driven motor 16' of a blower associated with itsdistributor coils, as well as a thermostatically controlled expansionvalve 16"; the reference numeral 17 generally designates a condenserunit, including a hydraulically or electrically driven blower motor 17',which is appropriately mounted fixedly to the forward end of the vanbody 12, at an elevated point above cab 11, so as to be exposed to theair current in transit and to be exposed to a minimum of dirt and dust;and the reference numeral 18 in general designates a direct mechanicalpower connection between the engine 18' of the Vehicle (Figs. 1 and 2)beneath the forward bonnet or hood 19 of vehicle 10. The referencenumeral 18" in Fig. 2 designates a conventionally shown resilient mountfor the engine 18 on a part of the vehicle chassis 15, schemticallyindicated as its front framework. The power connection 18 includes aforward electric clutch 20 and a flexible shaft 21 direct driven fromclutch 20 and rearwardly coupled rigidly to an auxiliary shaft of unit14, to be described.

Circulatory lines connecting compressor-motor power generating unit 14with condenser unit 17 and an evaporator and heat exchange unit 16 arealso depicted in schematic fashion in Figs. 1 and 7. These include theusual refrigerant liquid discharge line 22 from the compressor of unit14 to condenser unit 17 and evaporator heat exchange 16, a refrigerantreturn or suction line 24 connecting the compressor with heat exchangeunit 16; and hydraulic feed and return lines 25, 26, respectively, bywhich hydraulic power liquid is circulated between a hydraulic pump ofunit 14 and the units 16, 17, to drive the respective blowers or fans ofthose units. The blowers or fans will be, in accordance with theembodiment of the invention chosen for illustration, actuated bysuitable hydraulic gear motor 16', 17' (Fig. 7). However, it is to beunderstood that in an alternative adaptation these units may beelectrically energized, in which case the component of unit 14 whichpowers the motors will be a suitable electric generator, rather than apump. An appropriate receiver (so captioned in Fig. 7) is provided inthe refrigerant discharge line 22 behind condenser 17 and is actually apart of the condenser unit 17. The connections of the circulatory lines22, 24, 25 and 26, are diagrammatically shown in Fig. 7.

As more or less schematically shown in Figs. 3 and 4 of the drawings,the combined compressor-stand by motor-pump unit 14 comprises acompressor 28 of conventional character having a multiple sheave drivepulley 29 fixed to its shaft, which pulley receives a V-belt or belts 30by which it is driven from a further multiple sheave pulley 31 on anauxiliary stub shaft 32 of the unit 14. Shaft 32 parallels the mainpropeller shaft 33 of the vehicle (Fig. 1) and is journalled at its endsby bearings 34 supported by platform or framework 35 secured to thechassis 15 of the vehicle in an improved way, as will be described.

An additional sheave 36 on compressor shaft pulley 29 receives a furtherV-belt 37 by which a power generating device 38, such as a hydraulicpump is driven when compressor 28 is driven. Belt 37 is trained about apulley 38' on the pump shaft.

Alternatively, as indicated above, the power generating device 38 may bea suitable electric generator connected by appropriate wiring to theblower of heat transfer unit 16 and the fan of condenser unit 17. In aninstallation such as is shown herein, the hydraulic lines 25, 26(Fig. 1) will be appropriately connected to the hydraulic powergenerator 38 of Fig. 4 in an obvious manner. The term power device istherefore employed to designate either the electrical or hydraulic typeof power supply.

The compressor 28 and pump 38 are mounted on a common supportingplatform 39 of rigid, well-braced construction, of which the shaftjournalling frame work 35 of Fig. 3 may also be a part. The generalnature of the platform, minus bracket mounting means therefor, issomewhat schematically shown in Figs. 3 and 4. This supporting platformis sustained by a pair of brackets on the chassis 15 of the vehicle,which brackets may be of the general character shown in Figs. 5 and 5Aof the drawings. The bracket, generally designated 40, is constructed ofT-shaped, horizontally and vertically flanged cross section and in anL-shaped outline, and affords a laterally extending central web 41against which a. depending marginal flange 42 of the platform 39 may berigidly secured (in one way depicted in Fig. 5A) as by bolting orwelding. Bolting is preferred, due to the ease and flexibility oflocation and assembly which it permits. Other ways of fastening theplatform and bracket may of course be resorted to; and Fig. 5A is to beconsidered simply a suggestion. A similar connection of the platform issimilarly made to a bracket at the opposite end of the support.Attaching arms 42 extend laterally inwardly from each of the uprightlegs 43 of the brackets 40, which arms are provided with elongatedapertures 44. Upright leg 43 has a stabilitizing and reinforcing flange45 welded along the innermost edge of its laterally extending web 41,and the flange 45 is also provided with a hole 46.

As illustrated in Fig. 5, the brackets 40 are placed in side by sideabutment of their flanges 45 with channel 47, the channel constituting alength of vehicle chassis 15, and appropriate fastening studs, bolts, orthe like, generally designated 48, are applied through the apertures 44,46 to lock the brackets 40 and supported platform 39 in place along theside of the chassis 15. The fastening device 48 applied to the upperflange of channel 47 may comprise a bolt 48 applied to the aperture 44,with a nut on the bolt and a spacer 48" and spring clip 48" coacting inclamping the upper arm 42 over the upper channel flange.

The fastener 48 applied to the lower channel flange is shown as a stud49 hooked at its inner end around the lower flange and drawn up by a nutto thrust the 8 bracket flange 45 against the outer surface of thechafltiel. The width of the unit 14 is such that it is received wellwithin the side limits of the vehicle, being shielded in a readilyaccessible location by a depending side portion or skirt of the vehiclebody 12, as shown in Fig. 1.

As appears in Fig. 5, the brackets 40 may be expeditiously applied tothe chassis channel member 47 without the need for drilling and thusweakening the latter. The arms 42 are locked on the top of the channel,with the upright flange in stable side engagement therewith; and studs49 hook around the bottom channel flange to lock the platform andbracket assembly securely in place.

Referring again to Fig. 3 of the drawings, an electric stand-by motor isdesignated generally therein by the reference numeral 50. It issupported, along with compressor 28 and pump 38, on the platform 39,which is intended to afford a common mount for all of theinstrumentalities having a common drive, along with compressor 28, fromthe front to rear, clutch controlled drive connection 18 (Fig. 1).Indeed, it is contemplated by the invention that the framework 35 (Fig.3) by which the auxiliary drive shaft 32 is sustained shall also beappropriately supported by platform 39, so as to enable the entiresub-assembly 14 and the mechanical driving provisions therefor to besustained rigidly but removably on the vehicle chassis 15.

A multiple sheave pulley 51 is mounted on the shaft of motor 50, for thepurpose of stand-by operation of auxiliary shaft 32. V-belts 52drivingly connect the pulley 51 with a larger diameter pulley 53 onauxiliary shaft 32, and the driving connection of pulley 53 is effectivethrough the agency of an overrun or one-way clutch 54, which will enablethe motor drive of shaft 32 in one direction to operate the compressor28 and power pump 38 of unit 14, but will not permit the shaft 32 torotate motor 50. The importance of this protective feature in preventingdamage to or destruction of motor 50 at the relatively high speeds atwhich the compressor 28 and generator 38 are driven through the flexibleshaft connection 18 has been referred to in the preceding description.Motor 50 is de-clutched from the system during road operation.

The improved and simplified, direct engine drive connection 18 isillustrated adequately, as to its structural details and as to its frontend mounting in Fig. 2 of the drawings. The flexible shaft component 21thereof is conventional in character and requires no furtherillustration. It extends beneath the vehicle engine and chassis 16, andbeneath the operators cab 11, to the forward bearing 34 of auxiliaryshaft 32 (Fig. 3) at which point the flexible shaft 21 is drivinglysecured to shaft 32.

As illustrated in Fig. 2, the driving cable 56 of flexible shaft 21 issurrounded by a flexible, non-metallic sheath 56 and is fixedlyconnected to the output shaft 57 of electrically controlled clutch 20,which shaft is mounted by ball bearings 58 in a rearwardly extendingclutch housing 59 which is in fixed association with the housing offlexible shaft 21.

This rear housing 59 of the clutch 20 is clamped in an appropriatecollar 60 which is bolted in depending relation to a rigid mountingplate 61 having a central aperture to accommodate the further coil andarmature components of clutch 20, to be described.

As illustrated in Fig. 2, the mounting plate is sustained by a pluralityof studs 62 loosely received in apertures of plate 61, which studs arethreaded into a further rigid base plate 63; and the plate 63 is rigidlyclamped by bolts 64 to the front cross framework 65 of the vehiclechassis 15. A spacing shim 66 is preferably interposed between frame 65and base plate 63 in order to impart a necessary slight downward tilt tothe clamped clutch housing 59, so as to align the same with the housingof flexible shaft 21.

Coil springs 67 encircle the plate supporting studs 62 and are placedunder compression in the assembly, thus providing a cushioned,vibration-absorbing mount for the electrically energized clutch 2t) andassuring a long, trouble-free life of the latter under very severeoperating conditions. In accordance with the universal practice, thevehicle engine has a floating mount on the chassis. Hence the cushioningof the clutch mounting enables the clutch to follow and accommodatemovements of the engine, thus maintaining constant tension of the beltdriving the same (to be described).

As in the case of the mounting provisions for compressor-motor-generatorunit 14, the clutch mount just described is an exceedingly simple andinexpensive one, easily and inexpensively assembled to the vehiclechassis. The clutch 20 is in a conveniently accessible position, anddoes not occupy space within the engine hood 19 to obstruct access toengine parts. In short, the clutch mount carries out the underlyingobjective of the invention to permit assembly of the system to theVehicle with an absolute minimum of modification of the vehicle itself.Thus, the improved system is in a maximum degree standardized andadaptable for installation in truck designs of various types and sizes.

As indicated above, the electrically controlled clutch 20 asspecifically illustrated in Fig. 2 is of a conventional type, hence, thedescription of its details will be brief. It includes a rotatable drivenplate or disc 69 which is fixed to the forward pilot end of the clutchoutput shaft 57 by means of an integral hub 70. Disc 69 has annularouter recess which accommodates annular electrical coil 71 of theclutch.

A driving pulley 72 of clutch 2G is journalled for free rotation ondriven disc hub 69 by ball bearings 73, and the pulley 72 is continuallydriven by a V-belt 74 from the crankshaft of the engine 18 of thevehicle when the engine is operating. In accordance with theconventional design of the clutch 20, the pulley 72 is connected bymeans of a plurality of flexible drive arms 75 with the disc armature 75of the clutch, which armature is attracted against the friction disc 77on clutch driven plate 69 when the coil 71 of the clutch is electricallyenergized.

In accordance with one of the essential objects of the invention,provisions are made to protect the clutch 20 and its connected flexibledrive shaft 21 against damage in operation. The nature of the flexibleshaft 21 and its cable 56 necessitates such protection against abruptshocks of connection, particularly at a high road speed. Provisions forthis purpose are schematically illustrated in Fig. 6 of the drawings.

Referring to Fig. 6, it is seen that the clutch 20 is appropriatelygrounded to the vehicle chassis and its coil 71 is connected in acircuit through the ignition switch 79 of the vehicle (which may also beconsidered for simplicity to represent a manually operable controlswitch for the circuit independent of the ignition) and the vehiclebattery 24 by means of an electrical time delay unit 31 and an automaticcontrol unit 82. A conventional starter 83 for the stand-by motor 50 isconnected in parallel with this time delay circuit.

The unit 82 may be of an appropriate bellows type, including acorrugated flexible bellows 84 pressure connected by a line 85 with ahigh pressure line of the refrigerating system, and a further flexiblecorrugated bellows 86 connected by a line 87 with the low pressure lineof the system, or alternately with a temperature sensing bulb ascustomarily used in a thermostatically controlled system. The bellows84, 86 control the opposite movements of a contactor 88 which is adaptedto make and break a circuit through the fixed contacts 89. Thusexcessively high pressure on the high side of the system or low pressureon the low side will cause the circuit to be broken and operationstopped until the condition changes. With a thermostatic control theattainment of desired low temperature in the refrigerated interior, foran excessively high pressure, will stop the apparatus.

The delay unit 81 simply comprises a parallel hookup of a suitableswitch device and an adjustable potentiometer 91. The device 99 is abimetallic type, and an electrical circuit is completed therethroughafter a predetermined interval amounting to, say, three seconds to fiveseconds after closure of switch unit 82.. During this interval, thereduced current flowing through potentiometer 91 through coil 71 causesthe armature disc 76 of clutch 20 to be engaged with driven disc 69under partial force, resulting in a somewhat impositive clutchconnection. The clutch locks positively when the circuit is completedthrough bimetallic switch device 90. Thus a stepped engagement of theclutch results which frees flexible shaft 21 of the abrupt shock ofinitial connection. Full driving torque is transmitted after the delayinterval described.

Various modifications of the system described above are contemplated.For example, in some installations it may be desirable to arrange themechanically driven components in their entirety in a positioncorresponding to that occupied by the condenser unit 17 in Fig. 1; thiswould be made possible by transmitting engine power through a suitableflexible shaft and gear box to such a top mounted unit. Anothermodification contemplates the mounting of the condenser unit 17 and theblower and coil unit 16 on a substantially common base enabling thiscombination to be arranged as a single unit at the front of the body 12and over the cab, the heat transfer coil and blower extending through anappropriate opening cut in the forward end of the body. Otheralternative adaptations will suggest themselves to those skilled in theart.

It is seen that the invention affords a mobile truck refrigerationsystem of great compactness, simplicity, Versatility and ease ofinstallation and servicing. Parts there: of normally subject to damagein operation are fully protected, as by the overrunning clutchconnection of motor 50 to auxiliary drive shaft 32 and the protective,stepped electrical engagement of engine driven clutch 20 by the circuitshown in Fig. 6.

It is believed that the operation of the system will be clear from theforegoing description. When the engine is in operation, a closure of theelectrical circuit, automatically through the thermostatic unit 82 andmanually through switch 79, occasions a progressive engagement of clutch20 to transmit power through the same and the flexible shaft connectionto the auxiliary shaft 32. Compressor 28 and hydraulic pump 38 of thecombined, chassis mounted unit 14 are driven, and the shaft 32 overrunsthe pulley 53 connecting the same with standby motor 50. When adequaterefrigeration is had, the thermostatic unit 82 breaks this drivingconnection. During a layover interval, the same closure of theelectrical circuit will cause motor starter 83 to energize stand-bymotor 86, which then drives auxiliary shaft 32 through the motor pulley51, belts 52, pulleys 53 and overrunning clutch 54. The pulley 31 isthus motor driven to actuate compressor 28 and pump 38 through the belts3i) and pulley 29, in case of the compressor, and the belt 37 and pulley36 and in the case of the pump 38. The blower and fan of the units 16,17 are driven at speeds in proportion to the speed of operation of thecompressor 28, Whether in the engine driven or the stand-by motor drivenphase of operation of the system, resulting in a perfect balancingproportionate to the amount of refrigeration which is being generatedand must be distributed and dissipated.

What we claim as our invention is:

1. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portion,a refrigerating unit including a compressor mounted by said chassisadjacent and within said skirt portion, a readily applicable bracketlikesupport mounting said unit on said chassis, comprising a bracket onwhich said unit is fixedly secured, said bracket having an uprightmember firmly engageable with an upright surface of a member of saidchassis, and means in nonpenetrative engagement with said chassis memberto clamp said bracket member to said chassis surface.

2. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portion,a refrigerating unit including a compressor mounted by said chassisadjacent and within said skirt portion, a readily applicable bracketlikesupport mounting said unit on said chassis, comprising a bracket onwhich said unit is fixedly secured, said bracket being of L-shapedoutline and horizontally and vertically flanged cross section, having anupright member firmly engageable with an upright surface of a mem ber ofsaid chassis, and a horizontal portion supporting said unit, and meansin nonpenetrative engagement with said chassis member to clamp saidbracket member to said chassis surface.

3. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portion,a refrigerating unit mounted by said chassis adjacent and within saidskirt portion, and a readily applicable bracket-like support mountingsaid unit on said chassis, comprising a generally L-shaped bracket, on alaterally projecting leg of which said unit is fixedly secured, theother leg of said bracket being firmly engageable with an uprightsurface of a member of said chassis, and means in non-penetrativeengagement with said chassis member to clamp said upright bracket leg tosaid chassis surface.

4. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portionalong a longitudinal side thereof, a refrigerating unit mounted by saidchassis adjacent and within said skirt portion, and a readily applicablebracket-like support mounting said unit on said chassis, comprising agenerally L-shaped bracket, on a laterally projecting leg of which saidunit is fixedly secured, the other leg of said bracket being firmlyengageable with an upright surface of a member of said chassis, saidother leg having a projecting arm engaging a top surface of said chassismember, and means in non-penetrative engagement with said chassis memberto clamp said upright bracket leg and arm to said chassis surfaces.

5. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portionalong a longitudinal side thereof, a refrigerating unit including acompressor mounted by said chassis adjacent and within said skirtportion, a readily applicable bracket-like support mounting said unit onsaid chassis, comprising a generally L- shaped bracket, on a laterallyprojecting leg of which said unit is fixedly secured, the other leg ofsaid bracket being firmly engageable with an upright surface of a memberof said chassis, and means in non-penetrative engagement with saidchassis member to clamp said upright bracket leg to said chassissurface.

6. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body having a vertical outer skirt portion,a refrigerating unit including a compressor and a motor mounted by saidchassis adjacent and within said skirt portion, said motor beingdisposed in compact adjacent relation to said compressor and havingmeans to drive the latter in that relation, a readily applicablebracket-like support mounting said unit on said chassis comprising abracket on which said unit is fixedly secured, said bracket having anupright member firmly engageable with an upright surface of a member ofsaid chassis, and means in non-penetrative engagement with said chassismember to clamp said bracket member to said chassis surface.

7. In a refrigerating system for a truck or like vehicle characterizedby a chassis and a van-like body, a refrigerating unit including acompressor and a motor mounted by said chassis, said motor beingdisposed in compact adjacent relation to said compressor and havingmeans to drive the latter in that relation, a readily applicablebracket-like support mounting said unit on said chassis, comprising abracket on which said unit is fixedly secured, said bracket having anupright member firmly engageable with an upright surface of a member ofsaid chassis, and means in non-penetrative engagement with said chassismember to clamp said bracket member to said chassis surface.

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